Section 9: Lichen Planus and Lichenoid Dermatoses

Question 1

Civatte, or colloid bodies, and hypergranulosis are seen in?

Answer 1

Lichen planus

Question 2

Lichenoid drug eruption: drugs? px?

Answer 2

ACE inhibitors, thiazide diuretics, antimalarials, β-blockers, TNF inhibitors, quinidine and immune checkpoint inhibitors (e.g. nivolumab)
Appears similar to LP but more generalized or in photodistribution

Question 3

Answer 3

Lichen striatus
Can be skin-colored, tan or hypopigmented appear over several days along lines of Blaschko (represent pathways of epidermal cell migration + proliferation during development)
Favors children (2-3 yrs). Acral sites can have nail dystrophy (onycholysis, splitting)
Resolves over months to few years
DDx: linear LP (koebner), Blaschkitis (multiple streaks; adults; relapsing course; trunk > extremities), subtle or inflamed epidermal nevus > linear GVHD (specific setting), linear porokeratosis, linear psoriasis.

Question 4

Answer 4

Lichen nitidus
“ball & claw” histopath
DDx: papular eczema, flat warts, lichen planus, frictional lichenoid dermatitis of the elbows and knees, lichen striatus (when lin- ear), secondary syphilis, lichen spinulosus, lichen scrofulosorum, actinic lichen nitidus
Rx: no specific therapy; can try topical CS or topical calcineurin inhibitors and for extensive disease, phototherapy

Question 5

Koebner phenomenon is seen in?

Answer 5

Question 6

Answer 6

Lichenoid drug eruption. Thick violaceous plaques on the shin of a patient receiving nivolumab

Question 7

Answer 7

Acute (exanthematous; eruptive) LP
Self limited: 3-9 months
Exclude lichenoid drug eruption, pityriasis rose, secondary syphilis

Question 8

Answer 8

Actinic LP
Sun-exposed sites, especially face, neck, dorsal aspect of arms Red-brown annular plaques or melasma-like appearance. Middle East, young adults, children

Question 10

What areas are favored by annular LP?

Answer 10

Favors axilla, groin/penis, extremities

Question 11

Answer 11

Annular LP
Favors axilla, groin/penis, extremities

Question 12

Answer 12

Atrophic LP
Large plaques with epidermal atrophy Later stage of disease
DDx: lichen sclerosus, Annular variant with loss of elastic, fibers centrally

Question 13

Answer 13

Bullous LP, Bullae within pre-existing lesions, Separation of epidermis from dermis with underlying lichenoid lymphocytic infiltrate

Question 14

Answer 14

Hypertrophic LP, Favors shins and dorsal feet Thick pruritic plaques with scale can develop SCC* Average duration – 6 years DDx: lichen amyloidosis, LSC,
rupioid psoriasis

Question 15

Answer 15

Inverse LP
Violaceous plaques, Axillae > inguinal or other major body folds, Overlap with LP pigmentosus as lesions resolve with hyperpigmentation

Question 16

Differential dx for LP pigmentosus?

Answer 16

Erythema dyschromicum
perstans, resolved inverse LP
Usually seen in skin phototypes III and IV Coexisting LP lesions in 20% of
patients

Question 18

LP/LE overlap favor which site?

Answer 18

Lesions favor acral sites, Spectrum – from only cutaneous LE to systemic LE

Question 19

Answer 19

Lichenoid drug eruption in a photodistribution. The patient was taking HCTZ. Note the sparing under the watchband

Question 20

Differential for lichen nitidus?

Answer 20

Papular eczema, flat warts, lichen planus, frictional lichenoid dermatitis of the elbows and knees, lichen striatus (when lin- ear), secondary syphilis, lichen spinulosus, lichen scrofulosorum, actinic lichen nitidus

Question 21

Distribution of Erythema Dyschromicum Perstans (Ashy dermatosis)?

Answer 21

Favors neck, trunk, and proximal upper extremities; as in pityriasis rosea
Lesions follow skin cleavage lines “Langer lines”

Question 22

Erythema Dyschromicum Perstans prognosis?

Answer 22

In children, 70% resolve by 2 or 3 years
In adults, more chronic

Question 23

Differential for Erythema Dyschromicum Perstans?

Answer 23

Multiple fixed drug eruption (lesions more circular and browner color), postinflammatory hyperpigmentation (e.g. previous lichenoid drug eruption, pityriasis rosea), lichen planus pigmentosus.

Question 24

Tx for ashy dermatosis?

Answer 24

no specific effective therapy; can try sunscreens and mild topical CS

Question 25

Answer 25

Keratosis lichenoides chronica. A Linear and stellate keratotic plaques. B Symmetrical distribution of linear and reticulated keratotic plaques admixed with small violaceous lichenoid

Question 26

What is Summertime Actinic Lichenoid Eruption?

Answer 26

Pinhead-sized papules in sun-exposed sites in young adults with darker skin phototypes (IV, V); histopathologic features similar to lichen nitidus.

Question 27

Answer 27

Annular Lichenoid Dermatitis (of Youth)
Limited number of annular red-brown lesions with central hypopigmentation; they are often 5–15cm in diameter and favor the groin and flanks. More commonly seen in children and young adults.
DDx: inflammatory morphea, mycosis fungoides, inflammatory vitiligo, figurate erythemas.

Question 28

Answer 28

Keratosis lichenoides chronica.
Crusted psoriasiform scaling plaques on the face.